The discovery of nouns
2. Classification of nouns in English
3. Nouns and pronouns
Semantic vs. grammatical number
1. Number in specific languages
2. Obligatoriness of number marking
3. Number agreement
4. Types of number
The discovery of nouns
The word "noun" comes from the latin nomen meaning "name." Word classes like nouns were first described by Sanskrit grammarian Pāṇini and ancient Greeks like Dionysios Thrax and defined in terms of their morphological properties. For example in Ancient Greek nouns can be inflected for grammatical case such as dative or accusative. Verbs on the other hand can be inflected for tenses such as past present or future while nouns cannot. Aristotle also had a notion of onomata (nouns) and rhemata (verbs) which however does not exactly correspond our notions of verbs and nouns. In her dissertation Vinokurova has a more detailed discussion of the historical origin of the notion of a noun.
Different definitions of nouns
Expressions of natural language will have properties at different levels. They have formal properties like what kinds of morphological prefixes or suffixes they can take and what kinds of other expressions they can combine with. but they also have semantic properties i.e. properties pertaining to their meaning. The definition of nouns on the top of this page is thus a formal definition. That definition is uncontroversial and has the advantage that it allows us to effectively distinguish nouns from non-nouns. However it has the disadvandage that it does not apply to nouns in all languages. For example in Russian there are no definite articles so one cannot define nouns by means of those. There are also several attempts of defining nouns in terms of their semantic properties. Many of these are controversial but some are discussed below.
Names for things
In traditional school grammars one often encounters the definition of nouns that they are all and only those expressions that refer to a person place thing event substance quality or idea etc. This is a semantic definition. It has been criticized by contemporary linguists as being quite uninformative. Part of the problem is that the definition makes use of relatively general nouns ("thing " "phenomenon " "event") to define what nouns are. The existence of such general nouns shows us that nouns are organized in taxonomic hierarchies. But other kinds of expressions are also organized in hierarchies. For example all of the verbs "stroll " "saunter " "stride " and "tread" are more specific words than the more general "walk." The latter is more specific than the verb "move." But it is unlikely that such hierarchies can be used to define nouns and verbs. Furthermore an influential theory has it that verbs like "kill" or "die" refer to events  and so they fall under the definition. Similarly adjectives like "yellow" or "difficult" might be thought to refer to qualities and adverbs like "outside" or "upstairs" seem to refer to places. Worse still a trip into the woods can be referred to by the verbs "stroll" or "walk." But verbs adjectives and adverbs are not nouns and nouns aren't verbs. So the definition is not particularly helpful in distinguishing nouns from other parts of speech.
Prototypically referential expressions
Another semantic definition of nouns is that they are prototypically referential. That definition is also not very helpful in distinguishing actual nouns from verbs. But it may still correctly identify a core property of nounhood. For example we will tend to use nouns like "fool" and "car" when we wish to refer to fools and cars respectively. The notion that this is prototypocal reflects the fact that such nouns can be used even though nothing with the corresponding property is referred to:
John is no fool.
If I had a car I'd go to Marakech.
The first sentence above doesn't refer to any fools nor does the second one refer to any particular car.
Predicates with identity criteria
The British logician Peter Thomas Geach proposed a very subtle semantic definition of nouns. He noticed that adjectives like "same" can modify nouns but no other kinds of parts of speech like verbs or adjectives. Not only that but there also doesn't seem to exist any other expressions with similar meaning that can modify verbs and adjectives. Consider the following examples.
Good: John and Bill participated in the same fight.
Bad: *John and Bill samely fought.
There is no English adverb "samely." In some other languages like Czech however there are adverbs corresponding to "samely." Hence in Czech the translation of the last sentence would be fine; however it would mean that John and Bill fought in the same way: not that they participated in the same fight. Geach proposed that we could explain this if nouns denote logical predicate with identity criteria. An identity criterion would allow us to conclude for example that "person x at time 1 is the same person as person y at time 2." Different nouns can have different identity criteria. A well known example of this is due to Gupta:
National Airlines transported 2 million passengers in 1979.
National Airlines transported (at least) 2 million persons in 1979.
Given that in general all passengers are persons the last sentence above ought to follow logically from the first one. But it doesn't. It is easy to imagine for example that on average every person who travelled with National Airlines in 1979 travelled with them twice. In that case one would say that the airline transported 2 million passengers but only 1 million persons. Thus the way that we count passengers isn't necessarily the same as the way that we count persons. Put somewhat differently: At two different times you may correspond to two distinct passengers even though you are one and the same person. For a precise definition of identity criteria see Gupta.
Recently the linguist Mark Baker has proposed that Geach's definition of nouns in terms of identity criteria allows us to explain the characteristic properties of nouns. He argues that nouns can co-occur with (in-)definite articles and numerals and are "prototypically referential" because they are all and only those parts of speech that provide identity criteria. Baker's proposals are quite new and linguists are still evaluating them.
Classification of nouns in English
Proper nouns and common nouns
Proper nouns (also called proper names) are the names of unique entities. For example "Janet" "Jupiter" and "Germany" are proper nouns. Proper nouns are usually capitalized in English and most other languages that use the Latin alphabet and this is one easy way to recognise them. However in German nouns of all types are capitalized. The convention of capitalizing all nouns was previously used in English but has long fallen into disuse.
All other nouns are called common nouns. For example "girl" "planet" and "country" are common nouns.
Sometimes the same word can function as both a common noun and a proper noun where one such entity is special. For example: "There can be many gods but there is only one God." This is somewhat magnified in Hebrew where EL means god (as in a god) God (as in the God) and El (the name of a particular Canaanite god).
The common meaning of the word or words constituting a proper noun may be unrelated to the object to which the proper noun refers. For example someone might be named "Tiger Smith" despite being neither a tiger nor a smith. For this reason proper nouns are usually not translated between languages although they may be transliterated. For example the German surname Knödel becomes Knodel or Knoedel in English (not the literal Dumpling). However the translation of placenames and the names of monarchs popes and non-contemporary authors is common and sometimes universal. For instance the Portuguese word Lisboa becomes Lisbon in English; the English London becomes Londres in French; and the Greek Aristotelēs becomes Aristotle in English.
Count nouns and mass nouns
Count nouns (or countable nouns) are common nouns that can take a plural can combine with numerals or quantifiers (e.g. "one" "two" "several" "every" "most") and can take an indefinite article ("a" or "an"). Examples of count nouns are "chair" "nose" and "occasion".
Mass nouns (or non-countable nouns) differ from count nouns in precisely that respect: they can't take plural or combine with number words or quantifiers. Examples from English include "laughter" "cutlery" "helium" and "furniture". For example it is not possible to refer to "a furniture" or "three furnitures". This is true even though the furniture referred to could in principle be counted. Thus the distinction between mass and count nouns shouldn't be made in terms of what sorts of things the nouns refer to but rather in terms of how the nouns present these entities. The separate page for mass noun contains further explanation of this point.
Some words function in the singular as a count noun and without a change in the spelling as a mass noun in the plural: she caught a fish we caught fish; he shot a deer they shot some deer; the craft was dilapidated the pier was chockablock with craft.
Collective nouns are nouns that refer to groups consisting of more than one individual or entity even when they are inflected for the singular. Examples include "committee " "herd" and "school" (of herring). These nouns have slightly different grammatical properties than other nouns. For example the noun phrases that they head can serve of the subject of a collective predicate even when they are inflected for the singular. A collective predicate is a predicate that normally can't take a singular subject. An example of the latter is "surround the house."
Good: The boys surrounded the house.
Bad: *The boy surrounded the house.
Good: The committee surrounded the house.
Concrete nouns and abstract nouns
Concrete nouns refer to definite objects—objects in which you use at least one of your senses. For instance "chair" "apple" or "Janet". Abstract nouns on the other hand refer to ideas or concepts such as "justice" or "hate". While this distinction is sometimes useful the boundary between the two of them is not always clear. In English many abstract nouns are formed by adding noun-forming suffixes ("-ness" "-ity" "-tion") to adjectives or verbs. Examples are "happiness" "circulation" and "serenity".
Nouns and pronouns
Noun phrases can be replaced by pronouns such as "he" "it" "which" and "those" in order to avoid repetition or explicit identification or for other reasons. For example in the sentence "Janet thought that he was weird" the word "he" is a pronoun standing in place of the name of the person in question. The English word one can replace parts of noun phrases and it sometimes stands in for a noun. An example is given below:
John's car is newer than the one that Bill has.
But one can also stand in for bigger subparts of a noun phrase. For example in the following example one can stand in for new car.
This new car is cheaper than that one.
CHAIR PAPER BOOK CAKE DRINK CANDY CAKE FUDGE SISSORS KEY BOARD SPEAKERS CAR BIKE PENCIL PEN
In linguistics grammatical number is a morphological category characterized by the expression of quantity through inflection or agreement. As an example consider the English sentences below:
That apple on the table is fresh.
Those two apples on the table are fresh.
The number of apples is marked on the noun — "apple" singular number (one item) vs. "apples" plural number (more than one item) — on the demonstrative "that/those" and on the verb "is/are". Note that especially in the second sentence this information can be considered redundant since quantity is already indicated by the numeral "two".
A language has grammatical number when its nouns are subdivided into morphological classes according to the quantity they express such that:
Every noun belongs to a single number class. (Number partitions nouns into disjoint classes.)
Noun modifiers (such as adjectives) and verbs have different forms for each number class and must be inflected to match the number of the nouns they refer to. (Number is an agreement category.)
This is the case in English: every noun is either singular or plural (a few such as "fish" can be either according to context) and at least some modifiers of nouns — namely the demonstratives the personal pronouns the articles and verbs — are inflected to agree with the number of the nouns they refer to: "this car" and "these cars" are correct while "*this cars" or "*these car" are ungrammatical.
Not all languages have number as a grammatical category. In those that do not quantity must be expressed either directly with numerals or indirectly through optional quantifiers. However many of these languages compensate for the lack of grammatical number with an extensive system of measure words.
The word "number" is also used in linguistics to describe the distinction between certain grammatical aspects that indicate the number of times an event occurs such as the semelfactive aspect the iterative aspect etc. For that use of the term see "Grammatical aspect".
Semantic vs. grammatical number
All languages are able to specify the quantity of referents. They may do so by lexical means with words such as English a few some one two five hundred. However not every language has a grammatical category of number. Grammatical number is expressed by morphological and/or syntactic means. That is it is indicated by certain grammatical elements such as through affixes or number words. Grammatical number may be thought of as the indication of semantic number through grammar.
Languages that express quantity only by lexical means lack a grammatical category of number. For instance in Khmer neither nouns nor verbs carry any grammatical information concerning number: such information can only be conveyed by lexical items such as khlah 'some' pii-bey 'a few' and so on.
Most languages of the world have formal means to express differences of number. The most widespread distinction as found in English and many other languages involves a simple two-way number contrast between singular and plural (car / cars; child / children etc.).